Project Summary Congenital heart defects are the most common and resource intensive birth defects managed in the United States with high morbidity and mortality. They are estimated to effect over 1 million US children and 1.4 million US adults and to result in ~200,000 life-years lost and >$6 billion in inpatient acute care costs per year. Significant disparities are known to exist in short-term outcomes and resource utilization. We have shown that children from low income neighborhoods have 18% higher risk-adjusted odds of in-hospital mortality, have 7% longer lengths-of-stay, and require 7% more perioperative resources than do children from higher income neighborhoods, even after controlling for the effects of race, public versus private insurance provider, and the hospitals at which these children ultimately receive surgical repair. Research on long-term outcomes and health expenditures is limited and mechanisms driving health inequities remain unknown. Greater than 50% of children with congenital heart disease are covered by Medicaid. We have partnered with the NY Department of Health and have clean, validated data for all Medicaid patient encounters over 15 years across NY State. We have developed methods of abstracting and linking locally-held clinical registry data to Medicaid files and have built an interdisciplinary team of pediatric cardiologists, cardiac surgeons, health services researchers, health economists, and NY Department of Health senior leadership to identify dimensions of healthcare access that could be targeted through center- or state-level interventions to reduce inequities. We propose linking pediatric cardiac surgical clinical registry data from across NY State, longitudinal Medicaid claims, Census Bureau data, geocoded data, and the National Death Index. We will use these data to accomplish the following Aims: 1) We will define 10-year risk-stratified, multi-dimensional outcomes (mortality and morbidities) and associated health expenditures for children undergoing congenital heart surgery across New York State; 2) we will develop novel longitudinal risk models for children with congenital heart disease that adjust for social determinants of health, and 3) we will test dimensions of healthcare access as modifiable drivers of health inequities among children in New York with congenital heart disease on Medicaid. Achieving our aims would 1) establish a comprehensive, population-based resource for longitudinal outcomes and health expenditure research, inclusive of not only in-patient data, but also out-patient, emergency room, pharmacy, rehabilitation, home healthcare, education records, and neighborhood-level social determinants of health for nearly half of all children undergoing congenital heart surgery in NY State, 2) generate a methodology for investigations on long-term outcomes and value applicable across multiple populations, 3) assess constructs of access as modifiable mediators of social determinants of health, and 4) position us to translate these findings into policy and care changes to reduce health inequities.